For silver halide color photographic materials, light-sensitive silver halide emulsions and so-called dye-forming couplers forming dyes by undergoing a reaction with the oxidation product of an aromatic primary amine developing agent are frequently used and it is well-known to use a combination of a yellow coupler, a cyan coupler and a magenta coupler as such dye-forming couplers.
In these couplers, a 5-pyrazolone series coupler which is frequently used as a magenta coupler presents serious problems for color reproduction such as the azomethine dye therefrom has a side absorption at about 430 n.m. and the absorption does not sharply decrease at the longer wavelength region.
Thus, for overcoming these problems, there are provided, for magenta dye image-forming couplers, a pyrazolobenzimidazole skeleton as described in British Pat. No. 1,047,612 and a pyrazolotriazole skeleton as described in U.S. Pat. No. 3,725,067. Also, recently, there is newly provided a 1H-imidazolo[1,2-b]pyrazole skeleton as described in Japanese Patent Application (OPI) No. 162548/84 (U.S. Pat. No. 4,500,630 and European Pat. No. 119741) (the term "OPI" as used herein refers to a "published unexamined Japanese patent application"), a 1H-pyrazolo[1,5-b][1,2,4]-triazole skeleton as described in Japanese Patent Application (OPI) No. 171956/84 (European Pat. No. 0119860), a 1H-pyrazolo[1,5-d]-tetrazole skeleton as described in Japanese Patent Application (OPI) No. 33552/85 (Research Disclosure, No. 24220), and a 1H-pyrazolo[1,5]-pyrazole skeleton as described in Japanese Patent Application (OPI) No. 43659/85.
However, although these couplers may overcome the above-described hue problems, there is a problem that since the conversion of the coupler into an azomethine dye is low in the case of processing under the condition of forming a sufficient amount of the oxidation product of an aromatic primary amine developing agent in the silver halide emulsion layer (hereinafter, the conversion is referred to as coloring efficiency), the maximum coloring density (Dmax) is reduced.
For increasing the coloring efficiency, a method of introducing a releasable group at the coupling active position of a coupler, a method of adding a coloring increasing agent, a method of changing the ballast group of the coupler into one fitting to the coupler skeleton, etc., are known.